/**
 * Copyright 1996 self.com.au
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. (http://www.apache.org/licenses/LICENSE-2.0)
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed 
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for 
 * the specific language governing permissions and limitations under the License.
 *
 * <dhamma-message src="Atisha (11th century Tibetan Buddhist master)">
 * 	The greatest achievement is selflessness. The greatest worth is self-mastery.
 * 	The greatest quality is seeking to serve others. The greatest precept is continual awareness.
 * 	The greatest medicine is the emptiness of everything. The greatest action is not conforming with the worlds ways.
 * 	The greatest magic is transmuting the passions. The greatest generosity is non-attachment.
 * 	The greatest goodness is a peaceful mind. The greatest patience is humility.
 * 	The greatest effort is not concerned with results. The greatest meditation is a mind that lets go.
 * 	The greatest wisdom is seeing through appearances. 
 * </dhamma-message>
 *
 * @author Ashin Wimalajeewa
 *
 * Note, this is a very old runtime library that I have evolved since 1996. I rarely use it
 * now because the Apache Commons project has made it obsolete.
 */
package self.io;

import java.io.IOException;
import java.io.InputStream;

public class StreamDetector {
    /**
     * checks the first 1024 bytes of the stream for predominately binary
     * characteristics.
     * @param is - the stream to perform detection on 
     * @return true in 1st index position if stream is considerd a binary stream;
     * 			true in 2nd index position if the stream was rewound
     * @throws IOException
     */
    public static boolean[] isBinaryContent(InputStream is) throws IOException {
    	boolean[] ret = new boolean[] {false, is.markSupported()};
        byte[] buffer = new byte[1024];
        int read = 0;
    	try {
            is.mark(1024);
    		read = is.read(buffer);
            int binaryCount = 0;
            for (int i = 0; i < read; i++) {
                byte b = buffer[i];
                if (b == 0) {
                    ret[0] = true;
                    break;
                }
                if (b < 0x07 || (b > 0x0d && b < 0x20) || b > 0x7F) 
                    binaryCount++;
            }
            if (!ret[0] && read > 0 && binaryCount * 1000 / read > 850) 
            	ret[0] = true;
            return ret;
    	} finally {
			if (ret[1])
				is.reset();
    	}
    }
}